(CNN) - Three days after Mississippi's bitter Republican Senate primary runoff ended, the challenger in the race refuses to concede, charging that "this was not a fair election. Activity was illegal, at worst. Unethical, at best."
And in an exclusive interview with CNN affiliate WLOX, state Sen. Chris McDaniel said he was shocked at how fellow Republicans verbally attacked him after he announced a primary challenge against six-term Sen. Thad Cochran.
McDaniel, who enjoyed strong support from tea party and anti-establishment groups, narrowly edged out Cochran in the June 3 primary, but with neither man cracking 50% (there was a third Republican candidate on the ballot who grabbed 1.5% of the vote), the contest moved to Tuesday's runoff, which Cochran won by fewer than 7,000 votes.
Cochran's victory was aided votes from African-American Democrats, who were actively courted during the runoff campaign by pro-Cochran forces. According to Mississippi law, voters are not required to register with a political party, and anyone who doesn't vote in a primary election can cast a ballot in either party's runoff.
But McDaniel told WLOX on Thursday that his camp has already found irregularities in Tuesday's election.
"Republicans are supposed to choose the Republican nominee in the U.S. Senate. That's not what happened here. Thirty-five- to 40,000 Democrats jumped into this race and apparently tried to decide it. They have their own primary. We have ours. What we're looking for right now is irregularities. We already found hundreds, and we're going to keep looking," McDaniel said.
McDaniel added that those irregularities include people who first voted in the Democratic primary, then illegally crossed over to vote in the Republican runoff.
McDaniel repeated his earlier vow to use every legal maneuver available to fight Tuesday's results, adding that "integrity of elections matters. It always has mattered."
And McDaniel he said that the pro-Cochran forces should be ashamed of the strategy they used in urging black Democrats to vote for the senator.
"They called me a racist. They used race-baiting tactics. They scared people to the polls. That's no way to behave. They used people, and that's no way to behave," he said.
More than 61,000 more people voted in Tuesday's runoff than in the June 3rd Senate primary. It's extremely rare that turnout increases in a runoff election. And turnout in Mississippi's majority African-American districts increased at a much higher rate than overall turnout.
But those who backed Cochran defend their actions.
In an interview with CNN Chief Congressional Correspondent Dana Bash on Wednesday, Henry Barbour, the nephew of former Mississippi Gov. Haley Barbour, who steered the pro-Cochran Mississippi Conservatives, said, "In America, we have a right to vote. And in Mississippi, we don't register by party. So whites and blacks get to vote in the Republican primary if they decide, and I think the Constitution gives them that right. So, I'm afraid he's [McDaniel] wrong, I mean, people have a right to vote and I'm damned proud to have asked them for their support."
And Barbour said that some Democrats may have been converted.
"I'll tell you, some of the Democrats that we were recruiting to vote for Sen. Cochran - some of them have called me talking about switching," Barbour said. "This is how you grow."
In the interview with WLOX, McDaniel also said he has "no hard feelings" toward Republican leaders in Mississippi, but that he is still shocked at how they attacked him.
"I never thought that me, as a two-term Republican elected official, would be treated the way I was. It was character assassination. They [fellow Republicans] attacked me every chance they got. They ridiculed me. They mocked me. And that was an about-face from the way they treated me just prior to my primary challenge."
CNN Political Editor Paul Steinhauser contributed to this story